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Poster: Moose Malloy Date: Nov 25, 2009 5:35am
Forum: feature_films Subject: Re: MPEG4 to MPEG2

I can offer you a very rough guide to correcting audio-sync on Mpeg2 files - without re-encoding anything -- but it's a pain.

First split (demux) the audio&video from the file with TMPGEnc. It's the "simple demultiplex" tab - via MpegTools on the its menu. This will leave you the video file (with a .m2v suffix) and the audio file (with a .ac3 suffix).

Next, play the *original* Mpeg2 file in VlcPlayer. Use VlcPlayer's synchronization tool to find out how much the audio is out -- usually its about c.250ms either way. Adjust the value till you get everything in sync - then note the value. To get to this tool, press the little "graphic equaliser" button on VLC's window, then click on the synchronization tab.

Next, load up the little program DelayCut - and drop the audio file you created via TMPGEnc (example.ac3) onto the DelayCut window. In the Delay box, input the value you noted into the "Start (msec)" input-box. Now hit "process" and the program will fix your audio file WITHOUT re-encoding it!

Lastly, combine the .m2v file from TMPEGEnc with your fixed.ac3 from DelayCut. I use the program DVDFlick to put these together.
[UPDATE: I forgot to mention -- to stop DVDFlick re-encoding the video, check the box "copy Mpeg-2 streams" which is under "advanced" in the video section of the project settings]

All the above mentioned programs are free to use.

If you get stuck, feel free to ask.

Lastly, there are probably simpler ways to do all this - but this is the crazy scheme I've been using for a while and it always works for troublesome files.

This post was modified by Moose Malloy on 2009-11-25 13:35:37